Quaternary ammonium salts have been known for over 20 years to be effective as skin and hair conditioning agents. In applications of this type a quaternary, containing a long chain alkyl group of from 8 to 24 carbons, binds to the surface of the skin or hair and by virtue of the hydrophobic nature of the alkyl chain serves to "lubricate" the substrate surface. This lubrication manifests itself as a smooth, silky after-feel when the quaternaries are applied to skin or in the reduction of force needed to achieve combing when the compounds are applied to hair.
Some of the more recent examples of the use of quaternaries in the skin and hair conditioning area can be seen in U.S. Pat. No. 4,183,917 to Iwao et al. who disclose a hair conditioner composition containing the quaternary distearyl dimethyl ammonium chloride and U.S. Pat. No. 3,577,528 to McDonough et al. which describes the use of unsaturated long chain quaternaries in a two phase hair conditioner.
Patel et al. describe in U.S. Pat. No. 4,726,945 a conditioning system containing a mixture of a diquaternary ammonium salt, stearyl alcohol, stearamidopropyl dimethylamine, and cyclomethicone which is reported to not build up on the hair and to be able to be removed during washing. Furthermore, Connor et al. in U.S. Pat. No. 4,012,398 teach that the product achieved by reacting ethylene chlorohydrin or bromohydrin with an amide obtained through the condensation of mink oil with either dimethylaminopropylamine or diethylaminopropylamine exhibits conditioning properties as well as emolliency.
The patent literature is replete with references to the conditioning properties of quaternaries, but generally speaking, those materials which demonstrate acceptable conditioning exhibit the negatives of build-up, defoaming of surfactant systems, incompatibility with water-based materials, incompatibility with anionic surfactants, and such low levels of water solubility as to make a clear shampoo or similar formulation an impossibility.
The class of compounds known as alkylamido dimethyl 2,3-dihydroxypropyl ammonium salts has been described in U.S. Pat. No. 2,589,674 to Cook et al. as being useful as wetting agents, detergents, emulsifying agents, germicides and fungicides, but their use has not been described in hair or skin conditioners.